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For any respiratory sound analysis or assessment, respiratory flow must also be measured simultaneously with the sounds. However, due to difficulties and/or inaccuracy of the most flow measurement techniques, several researchers have attempted to estimate flow from respiratory sounds. However, all of the proposed methods heavily depend on the availability of different rates of flow for calibration...
It is said that sleep apnea syndrome is one of the main causes of airplane, train and car accidents. We have developed a non-contact breathing measurement system which diagnoses not only sleep apnea syndrome but also other sleep disorders. This system calculates the amount of the volume change and makes the movement of the outside of the body by the breath motion visible. If the patient is breathing...
Heart beat is an unavoidable source of interference during lung sound recording. This disturbance is more significant at low and medium breathing flow rates. Removing heart sounds (HS) from lung sound recordings or vice versa is a challenging task but of great interest for respiratory specialists and cardiologists. In this study, to separate the two signals, a novel HS separation method based on independent...
Frequent arousals during sleep degrade the quality of sleep and result in sleep fragmentation. Visual inspection of physiological signals to detect the arousal events is inconvenient and time-consuming work. The purpose of this study was to develop an automatic algorithm to detect the arousal events. We proposed the automatic method to detect arousals based on time-frequency analysis and the support...
Very slow yogic breathing techniques provide valuable insights into mechanisms of autonomous nervous system regulation that are usually not available for human subjects. This paper presents results of eight sessions of Nadi Shodhana Pranayama practiced at rate of one breath per minute. We characterized statistic and spectral measures of heart rate variability before, during, and after exercises. Significant...
In this paper, we propose a measuring device implementation to measure ECG, 50 KHz BIA for getting BIA/respiration, and 10~50 Hz GSR for measuring electrical characteristics of skin. To this end, BIA signal is separated by line filter and high impedance element and the interference between signals could be minimized by switching in time domain to separate ECG and GSR signals having the similar frequency...
The maximum left ventricular elastance (Elvmax ) is a valuable index of ventricular contractility. However, conventional methods for its measurements are too invasive for routine use. We propose a non-invasive technique for tracking changes in Elvmax by mathematically determining the dynamic coupling between beat-to-beat fluctuations in instantaneous lung volume and arterial blood pressure measured...
Current alarm strategies for physiological monitoring depend on predetermined thresholds without consideration for the heterogeneity between patients or intraoperative variations. To improve upon this situation, we developed an adaptive change point detection scheme to automatically notify the clinician when a change of clinical significance has occurred in the respiratory variables. We modeled end-tidal...
Sleep apnea syndrome (SAS) is a very common sleep disorder disease. Reliable detection of apnea is very crucial for subsequent treatment. In this article, a novel method based on artificial neural network is proposed for such purpose. With its time-invariant property the time delay neural network (TDNN) is adopted in this system to employ the temporal trend of apnea event. As airflow and SaO take...
A wearable system able to monitor cardiopulmonary vital signs is presented. The innovative technological core of the system is based on the use of a textile conformable sensing cloth, where conducting and piezoresistive materials are integrated in form of fibres and yarns, giving rise to fabric sensors, electrodes and connections. Electrocardiogram and impedance pneumography signals are acquired through...
We applied time-variant and time-invariant parametric models in both healthy subjects and patients with sleep disorder recordings in order to assess the skills of those approaches to sleep disorders diagnosis in wearable devices. The recordings present the obstructive sleep apnea (OSA) pathology which is characterized by fluctuations in the heart rate, bradycardia in apneonic phase and tachycardia...
Impulse oscillometry (IOS) is an innovative patient-friendly pulmonary testing technique which measures the respiratory system impedance (Z) by using the spectral components of pressure to flow ratio which yields resistance and reactance values at different frequencies. The high dimensionality of IOS measurement data makes the analysis of this information difficult. Artificial neural networks (ANNs)...
Using a Volterra-Wiener model and the Laguerre expansion technique, we estimated in a previous study the parameters that characterize linear and the second order effects of respiration ("RSA") and arterial blood pressure ("ABR") on heart rate. RSA and ABR gains were significantly lower in obstructive sleep apnea (OSA) patients than in normal subjects. During sleep, ABR gain increased...
The electrocardiogram (ECG) is a representative signal containing useful information about the condition of the heart. The shape and size of the P-QRS-T wave, the R-R interval etc. may help to identify the nature of disease afflicting the heart. However, human observer can not directly monitor these subtle details. Hence, the fusion of ECG, blood pressure, saturated oxygen content and respiratory...
The objective was to compare the accuracy of estimations of respiratory rate (RR), based on tracheal sounds, with simultaneous estimations from a capnograph, using as a common reference a pneumotachometer. Five subjects without pulmonary diseases were enrolled. Tracheal sounds were acquired using a contact piezoelectric sensor placed on the subject's throat and analyzed using a combined investigation...
The quantity analysis on solitary pulmonary nodules (SPN) is very important for pulmonary disease diagnosis and prediction, especially, in the early phase or small sizes. Due to the breathing activity of patients, the SPN region is translated and deformed after the injection of bolus so that it is hard to obtain the exact enhancement patterns. In this presentation, we give an approach to combine plain...
This work proposes multichannel acquisition of lung sounds by a microphone array, feature extraction by a multivariate AR (MAR) model, dimensionality reduction of the feature vectors (FV) by SVD and PCA and, their classification by a supervised neural network. A microphone array of 25 sensors was attached on the thoracic surface of the subjects, who were breathing at 1.5 L/sec. The supervised neural...
Classical models of respiratory control assume a hardwired system architecture with reflex regulation of respiratory rhythm and total ventilation. Recent experimental studies, however, reveal a much more pliable architecture with varying forms of neural plasticity in the afferent and efferent pathways. Here, mathematical models of several types of neural plasticity are proposed and their computational...
Assessing autonomic control provides information about patho-physiological imbalances. Measures of variability of the cardiac interbeat duration RR(n) and the variability of the breath duration T Tot(n) are sensitive to those changes. The interactions between RR(n) and TTot(n) are complex and strongly non-linear. A study of joint symbolic dynamics is presented as a new short-term non-linear analysis...
Congenital central hypoventilation syndrome (CCHS) is a rare disorder with failure of automatic control of breathing, defined by lack of an appropriate ventilatory response to hypercarbia and hypoxia. However, more detailed evaluation of cardiorespiratory coupling has not been previously performed in those with CCHS. We postulate that those with CCHS have disjointed cardiorespiratory responses to...
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